Project description:Mesocosms (600 L) were deployed at the Southern Ocean Time Series (SOTS) in Austral late summer during a high nutrient, low chlorophyll period. One mesocosm represented control, present-day conditions (high nutrients/low temperature/low pCO2/low Fe/low irradiance), while the other was amended to represent a projected 2100 scenario (low nutrients/high temperature/high pCO2/high Fe/high irradiance). Approximately 2 L were filtered from the mesocosms onto 5 µm filters at Days 0, 2, 4, and 7 of the incubation.
Project description:Methylomicrobium buryatense 5GB1 is an obligate methylotroph, which grows on methane or methanol with similar growth rates. Core metabolic pathways are similar on both substrates, but recent studies of methane metabolism suggest that growth on methanol might have significant differences from growth on methane. In this study, both a targeted metabolomics approach as well as a 13C tracer approach have been taken to understand core carbon metabolism in M. buryatense 5GB1 during methanol growth, to determine whether such differences occur. Targeted metabolomics analyses were performed on both methane and methanol cultures to identify metabolic nodes with altered fluxes. Several key metabolites showed significant differences in pool size. Noticeably, 2-keto-3-deoxy-6-phosphogluconate (KDPG) showed much larger pools under methanol culture, suggesting the Entner-Doudoroff (ED) pathway was more active. Intermediates in other parts of metabolism also showed differences in pool sizes under methanol growth. A systematic shift of active core metabolism is proposed to explain the changes. In order to distinguish flux partition differences at the C3-C4 node, 13C tracer analysis was also applied to methanol-grown cultures. Using the experimental results as constraints, we applied flux balance analysis to determine the metabolic flux phenotype of M. buryatense 5GB1 growing on methanol. The resulting new insights into core metabolism of this methanotroph provide an improved basis for future strain design.
Project description:Current advances in genomics and computational biology have afforded novel insight as to how the phenotype is generated from the genotype – systems biology. We argue that systems biology, when viewed through an ecological lens, provides an unprecedented opportunity to understand how genes cascade through multiple levels of biological organization to alter ecosystem function. To test this approach, we established six monocultures of Arabidopsis thaliana ‘Columbia’- wild-type plants, six monocultures of a single gene variant (mutant) to the wild-type, and six mixtures with equal density plantings of each genotype in mesocosm chambers (50 x 50 x 45 cm). The mutant harbored a T-DNA insertion in the main nitrate reductase gene (nia2). This is the gateway enzyme for N metabolism, which resulted in activity levels that were 38% of the wild-type. Mesocosms were instrumented to monitor soil and air temperature, water and humidity status, and CO2 differentials. Transcript expression profiles were generated for each of the monoculture populations by collecting and processing 100 leaves per mesocosm at generation 2 and 4.
Project description:Tropical maize genotypes are well known for their traits of late flowering and higher biomass. Carbon/Nitrogen balance in these genotypes is significantly different from temperate genotypes. Microarray analysis of gene expression changes occuring in developing earshoots was done and results were compared with the temperate genotype microarray analysis, previously conducted. A low yielding variety was used as a reference against three high yielding varities. Keywords: Genotype response Technical replicates, dye swaps, technical replicates of dye swaps, no biological replicates
Project description:Tropical maize genotypes are well known for their traits of late flowering and higher biomass. Carbon/Nitrogen balance in these genotypes is significantly different from temperate genotypes. Microarray analysis of gene expression changes occuring in developing earshoots was done and results were compared with the temperate genotype microarray analysis, previously conducted. A low yielding variety was used as a reference against three high yielding varities. Keywords: Genotype response
